April - June 2007 - Kasetsart University

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natural mineral soils, the soil samples were
collected from different sites of Somali region and
from Zeway area of East Showa zone, Oromiya
Regional State. The sites in Somali region were
selected from Jijiga and Shinile zones based on
the suggestion of Somali Regional Pastoral and
Agro Pastoral Research Institute (SoRPARI) and
the clan leaders. Soil samples were collected from
the sites (Arabi, Jair, Hermokale and Bole) where
pastoralists mostly use for mineral supplementation
to their animals. Individual natural mineral
soil was collected using hoe to the depth of 30 cm
from three different spots which fall in the radius
of 50 to 70 m. Soil samples were mixed together
and then filled into a plastic collection bag, labeled
and stored at room temperature. A total of four
composite soil samples from the study sites were
taken and analyzed for physical and chemical
properties at National Soil Laboratory for Research
Center (NSLRC). Analysis of each sample was run
in duplicate.
The pH and electrical conductivity of the
soils were measured according to the procedure
of Landon (1984). Ca, Mg, Fe, Mn, Zn, and Cu
were determined by atomic absorption
spectrophotometer (Lindsay and Norvell, 1978).
Sodium and potassium were analysed by flame
photometer (Black, 1965). Organic carbon was
determined following the wet digestion method
of Walkley and Black (1934). Available
phosphorus was determined following Olsen
methods (Olsen et al., 1954). Total nitrogen was
determined using the modified Kjeldahl method
(Jakson, 1958).
Liver tissue collection and analysis
A total of sixteen sheep (two sheep from
each treatment group) were randomly selected and
slaughtered to determine liver mineral contents.
Liver tissue samples of 50 to 100 g were taken
from the right lobule of liver of individual animal.
The samples were stored frozen until analysed for
Ca, Mg, Fe, Mn, Cu, Zn and Co using flame atomic
Kasetsart J. (Nat. Sci.) 41(2)
absorption spectrophotometer (Perkins-Elmer,
Model 2380).
Statistical analysis
Data were analyzed using the PROC
ANOVA procedure of SAS (1999). Differences
among treatment means were evaluated using
Duncan Multiple Range Test (Cody and Smith,
1997). The statistical model used was:
yij = µ+ Ti + εij
Where, Yij = Response variable (body
weight gain, mineral intake and mineral in liver
tissue)
µ = Overall mean
Ti = The effect of ith treatment
(i = 1, 2, 3, 4, 5, 6)
εij = Residual effect
RESULTS AND DISCUSSION
Physical properties of the mineral soils
Most naturally occurring mineral
deficiencies in livestock are associated with
specific regions, and they are related to both soil
mineral concentration and soil characteristics
(McDowell 1986). Physical properties of mineral
soils collected from different sites are presented
in Table 1. pH of the soil samples ranged from 8.0
for soils from Arabi to 9.5 for soils from Bole sites
indicating that they were alkaline in nature. The
pH values soils was higher than the pH values
(ranged from 7.86 to 8.05) of natural mineral soil
from Southern low lands of Ethiopia (Kabaija and
Little, 1987; Fikre, 1990). Colours of the soils
varied from site to site ranging from dark brown
to light brownish colours. The soil textures varied
from silt to loam. The soils in Jair and Hermokale
areas were predominantly silt loam but Arabi soil
were silt in texture whereas Bole soils were sandy
clay. The color and texture of individual natural
soils are as shown in Figure 1.